We found this circuit in a 1956 Sylvania publication. It serves to monitor telegraph transmissions being placed next to the transmitter. The circuit is indicated for the range of 80 and 160 meters.
We found this light relay circuit in year 2000 documentation. The relay is 6 V and the circuit...
We found this circuit in the Linear Technology Applications of 1997. The circuit uses components from...
We have dozens of similar projects in articles and circuits on this site. This is from Radio...